星载GNSS-R镜面点及空间路径初始化新方法  

A New Initialization Method for Specular Points and Space Paths Computation in Spaceborne GNSS-R

作　　者：宋敏峰 何秀凤[1] 王笑蕾 李伟强 SONG Minfeng;HE Xiufeng;WANG Xiaolei;LI Weiqiang(School of Earth Sciences and Engineering,Hohai University,Nanjing 211100,China;School of Marine Science and Technology,Tianjin University,Tianjin 300073,China)

机构地区：[1]河海大学地球科学与工程学院,江苏南京211100 [2]天津大学海洋科学与技术学院,天津300073

出　　处：《武汉大学学报（信息科学版）》2024年第1期131-138,共8页Geomatics and Information Science of Wuhan University

基　　金：国家自然科学基金(42304053,41830110);江苏省卓越博士后计划(2023ZB382)。

摘　　要：利用全球导航卫星系统反射(global navigation satellite system-reflectometry,GNSS-R)信号进行对地观测存在镜面点及空间路径初始化误差大的问题,由此提出了一种高效的星载多模GNSS-R镜面点及空间几何路径计算初始化新方法。基于大量仿真的星载GNSS-R反射事件,采用多项式对固定轨道条件下反射事件地心角和真实镜面点在直射信号路径上投影点至两颗卫星的距离比值进行建模,进一步拟合该模型系数与不同GNSS卫星轨道高度的变化趋势,得到参数系数随GNSS轨道高度的变化模型,从而建立新初始化方法。基于多系统多轨道的GNSS-R仿真数据实验表明,所提方法的初始化精度相对于已有方法从数百甚至1000 km提高至5 km左右;同时对比实验也表明,该模型可使得主流的迭代方法计算效率在掠射观测时提高79.1%。Objectives:In response to the problem of large initialization errors in specular point and geometric path computations in earth observation technology using global navigation satellite system-reflectometry(GNSS-R),an efficient new method for initializing multi-system spaceborne GNSS-R specular point estimation and geometric path computation is proposed.Methods:Based on a large number of simulated spaceborne GNSS-R reflection events,the ratio of the distance,between the projection point of the truth specular point on the direct path of the signal to the two satellites,and the geocentric angle of the reflection event under fixed orbit conditions is modeled using polynomials.Furthermore,the variation trend of these model coefficients with different GNSS satellite orbit heights is fitted to obtain a model of the variation of parameter coefficients with GNSS orbit heights,thus establishing the new initialization method.Results and Conclu⁃sions:The results of experiments based on multi-system multi-orbit GNSS-R simulation data show that the initialization accuracy of the new model is improved from hundreds or even thousands of kilometers to about 5 km compared with the existing methods,and the comparison experiments also demonstrate that the proposed method could improve the calculation efficiency of the mainstream iterative method by 79.1%in grazing observation.

关 键 词：星载GNSS-R 初始化方法 镜面点 空间路径 

分 类 号：P237[天文地球—摄影测量与遥感]